NASA’s Danielle Moser composed this image of about 120 Perseid meteors taken by the Marshall Space Flight Center’s All Sky Fireball Network station at Huntsville, Ala., on Aug. 13, 2015.

Whetting your appetite for cosmic backyard adventure, the Perseid meteors will peak this weekend, but to see them successfully, two ingredients are required: cloudless heavens and patience.

(Scroll down to the bottom of this post for a cloud cover forecast.)

For the 2017 edition of the annual Perseid shower, those shooting stars compete with a bright, waning gibbous moon. The official peak is predicted for Saturday in mid-afternoon Eastern, according to the Royal Astronomical Society of Canada. Saturday night — closest to this peak — presents the best opportunity for viewing.

Still, consider first checking out the heavens Friday evening, to see whether you can spot any Perseids before the fat moon rises. In Washington, the 84 percent-illuminated moon rises Friday night at 10:32 p.m., according to the U.S. Naval Observatory.

On Saturday evening, when the shower peaks and the chances of spying Perseids are maximized, the moon rises at 11:06 p.m.

Patience, clear skies and a refreshing summer beverage will serve you well. Turn off your porch lights, get away from streetlights and find your dark, happy space. Pull up a lawn chair, let your eyes adjust to the darkness for about 20 minutes to a half-hour outside, and look up.

For the peak, the Royal Astronomical Society of Canada predicts about 90 meteors an hour, but don’t give yourself false hope. You may find ample meteors before moonrise, but perhaps a handful after the moon’s brightness washes away all but the brilliant ones.

The Perseid meteors are the most consistent and productive of the annual meteor displays, said astronomer Geoff Chester of the Naval Observatory, who explained they are usually fast and bright. In his The Sky This Week, he said where the meteors appear to emanate — in the constellation Perseus — which rises in the eastern sky late in the evening. Under bright moon conditions, Chester suggests looking for meteors in the early morning hours when the constellation will be high in the northeast.

Happy trails! We see meteors because of dirty snowballs called comets. For the Perseids, thank Comet Swift-Tuttle — periodic comet 109P, discovered during the Civil War. As the comet swings by our planetary neighborhood, the sun heats it up and the comet leaves a dusty trail, composed of pebble-sized specks.

On its annual trip around the sun, Earth smacks into these dirty leftover trails. In turn, the flecks strike our atmosphere and burn up — giving us a gorgeous view of fiery bits streaking across our heavens: shooting stars!

Comet Swift-Tuttle was discovered concurrently by astronomer Horace P. Tuttle on July 19, 1862, at Cambridge, Mass., and Lewis Swift on July 16, 1862, at Marathon, N.Y. — just north of Binghamton. Incidentally, during the Civil War, Tuttle joined the Union Army and later became an astronomer at the Naval Observatory. Tuttle died in 1923 and is buried in an unmarked grave at Oakwood Cemetery in Falls Church, very close to Seven Corners, according to astronomer Richard Schmidt of the Naval Observatory.

The Perseids meteors last from now until about Aug. 26, when the numbers will be greatly diminished, according to the International Meteor Organization.

Stare up and be counted: If you want to submit your meteor count, you can join the International Meteor Organization. The group welcomes students and citizen-observers. Register here as a paid member or as a free user to submit your falling star counts.

In case of clouds or rain for the peak night, Slooh.com will present the Perseids live on the Web on Saturday, starting at 8 p.m. EDT. Join former sports broadcaster Gerry Monteux and astronomers Paul Cox and Bob Berman for this heavenly tour of racing stars.

Cloud outlook Saturday evening

National

The nation’s best viewing, where skies are most likely to be clear, focuses in the Southwest, the northern Ohio Valley and interior Northeast, and parts of the northern Rockies (east of Idaho).


European model cloud cover forecast for 11 p.m. eastern Saturday night. (StormVistaWxModels.com)

Clouds will tend to be most prevalent in the Southeast United States and eastern New England, where viewing prospects are poor.

Washington, D.C., area

Scattered thunderstorms are possible in the D.C. area into Saturday evening, but there’s a good chance they diminish and at least partial clearing begins after sunset. Between about 9 and 11 p.m. may offer a reasonable window for viewing, but check forecast updates Saturday.

Friday night viewing is a no-go, because of clouds and rain.

Capital Weather Gang chief meteorologist Jason Samenow prepared the cloud cover forecast.